1. Field of the Invention
The present invention relates to a method and apparatus for collecting fumes from a metallurgical vessel, such as a ladle, undergoing a cleanout operation. Such cleanout operations are performed to remove solidified material from, or to unblock, one or more discharge ports in the vessel.
2. Description of the Related Art
Many large metallurgical vessels such as ladles have one or more openings or ports provided on their bottom for discharging material such as molten metal, from their interior. After emptying of molten metal, these vessels begin to cool, relatively rapidly, typically resulting in residual metal or slag within the bottom interior of the vessel solidifying and blocking the vessel discharge ports. A cleanout operation must then be performed to remove the solidified material from the one or more ports on the bottom of the vessel. In order to access the ports, the vessel is typically tipped onto its side.
Removing solidified material, e.g. metal or slag, from these ports is often performed by using a high temperature lance torch. The lance end of the torch is inserted into the blocked port as solidified material is melted and blown out of the port. The lance torch is inserted into the port from the exterior of the ladle and pushed inward toward, and eventually into, the ladle interior. As will be appreciated, copious amounts of fumes or smoke are generated. The fumes or smoke often comprise harmful or hazardous chemicals. During the initial phases of a cleanout operation, fumes and smoke are generated along the exterior bottom or underside of the tipped vessel. Once the torch has penetrated the previously blocked discharge port, and thus, a passage or opening is established within the port, fumes and smoke also flow from the bottom of the vessel, within its interior. In order to collect the fumes or smoke, it would be desirable to utilize a movable hood that could be positioned adjacent to the source of the fumes or smoke, and then be moved out of the way after such collecting.
Positionable or movable fume collecting hoods are known in the art. For example, U.S. Pat. No. 3,380,371 to Scheel describes a movable hood assembly for collecting fumes from a ladle as it is transported from one area in a plant to another area. Scheel notes that the hood assembly is designed for attachment to either the ladle or its supporting structure, thereby enabling the hood to travel along with the ladle. A flexible hose or duct enables movement of the hood.
Another approach to providing a positionable hood is described in U.S. Pat. No. 4,379,548 to Boshoven. Boshoven eliminates flexible hose sections and instead utilizes a series of swivelable duct sections essentially cantilevered from a stationary base to achieve mobility at the distal hooded section.
Although satisfactory in many respects, these hood configurations are generally not usable when attempting to collect fumes from a vessel or ladle oriented on its side. Accordingly, there is a need for a movable hood and duct assembly for collecting fumes from a vessel oriented on its side. Moreover, there is a need for a system of collecting fumes emitted during a ladle cleanout operation which is often characterized by the emission of fumes and smoke along the bottom exterior of the ladle, followed by emission within the ladle interior.